Amazon has trained its Prime members to expect low prices. So naturally those shoppers have been reluctant to dish out for expensive groceries at Whole Foods.

...

Amazon has tried to make Whole Foods more attractive to Prime members since the acquisition. Amazon initially cut prices on products like salmon and avocados. Then it began offering an extra discount on sale items exclusively for Prime shoppers last year to sweeten the Whole Foods offer.

Despite those steps, most Prime members still avoid shopping at the organic grocery chain. Only about 18% of Prime members shop at Whole Foods at least once per month and 70% of Prime members say they rarely or never shop at Whole Foods, according to a recent survey by Wolfe Research.

Whole Foods' high prices have been a big reason why Prime members have stayed away. Although Amazon made splashy discounting moves at first, Whole Foods' prices have creeped back up in recent months and remain well above rival supermarkets.

...

Bigger chains like Kroger, Albertsons and Aldi have taken note of Whole Foods' appeal and expanded their own exclusive lines of organic foods. Kroger's Simple Truth grew 15% last year and is now a $2.3 billion brand. Aldi plans to expand its fresh food selection by 40% at its more than 1,800 stores across the country.

...

Whole Foods' prices have also been ticking back up as consumer goods' manufacturers such as Dr. Bronner's and Haagen-Dazs increase their costs, according to the Wall Street Journal. The newspaper reported that in February, Whole Foods raised prices from 10 cents to several dollars on hundreds of products.